Here is a list of all the postings Michael Checkley has made in our forums. Click on a thread name to jump to the thread.
Thread: 150cc Radial Engine - A restoration or new build... |
10/12/2017 17:27:49 |
Yesterday I wrote the program to mill the the inside of the pistons and following a few iterations committed to the actual 5 pistons which resulted in a few more iterations to the program. It seems that even after 3 practice runs there was still a lot to learn! Today I drilled and reamed one of the test pistons for the shoulder bolt soon to be gudgeon pin. The original plan was to use a dowel pin for the gudgeon pin but I wanted to hollow it out and didn’t think this would work out well. The 12.9 shoulder bolt fits well enough.
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02/12/2017 18:15:28 |
Liners are cast iron and aluminium parts are a mixture of 7075 and 6082. The plan so far is to use EN24T for the crankshaft which will be a little more substantial than the original to take a bit more abuse. I have used a few plans and books as reference but found that very few include a tolerance for critical dimensions, I guess most are made as a one off to fit the mating part. For this project I have chosen to go for a tolerance on all the critical features to enable me to make each part individually much like a more commercial/industrial item. So far so good and the fit of the parts is good, perhaps a little more in the scrap bin though! Next job is to finish off the pistons and make some gudgeon pins.
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02/12/2017 18:08:58 |
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02/12/2017 18:01:56 |
I have been working on a 5 cylinder radial engine for a couple of months now and the project has reached a stage where I have something to show for my efforts. As an introduction this is how I came about starting this project... My interest in model engineering came through making bits for model aircraft, a hobby which I have been involved with for about 20years flying most weekends and visiting most of the big shows throughout the year. Those that also enjoy this hobby and visit the shows will have seen Ray Slack flying a variety of large scale model aircraft some of which had his very own design and built radial engines! Ray flew in a model flying club not far from me and he often used to visit my club to display his aircraft giving me the opportunity to chat about model engineering type things. Sadly Ray passed away and like a lot of model engineers his equipment was divided up and dispersed. It was a few years later that I stumbled across his 5 cylinder engine in an aeromodellers shed. The engine had run for a couple of years since finding its new home but had reached a point of needing new parts and then eventually finding its way to becoming a boxed up collection of parts. As the new owner knew that I was a keen model engineer I was lucky enough to be given the engine for rework. Upon examination it was clear that new parts had been attempted and was now in need of a serious makeover. Ray based the engine around laser engine cylinder heads, valve gear, pistons and what looks like some kind of agricultural crank shaft. I couldn't identify the crankshaft and some of the laser engine parts needed replacing which when multiplied by 5 started to look costly. At this stage I decided to take a step back and 'draw up' the complete engine in CAD and then remake all the parts apart from (for now) the cylinder heads and valves. The plan is to split the project up in to stages ultimately replacing all the commercial parts (apart from the obvious like bearings) with machined from stock items making a complete home built engine. If my engine performs half as well as Ray`s original did then I will be doing well. The engine is ~150cc with a 34mm bore. I have changed the bore diameter a small amount to be able to use Zenoah piston rings as I didn't fancy making rings at this stage. This then meant moving away from the laser pistons and making my own. I have changed the bearing arrangement slightly to be more inline with my working life experience. Its a glow engine but in time I would like to have a go at a petrol conversion. Petrol radial engines are common place on the show circuit now so getting the bits should not be a problem. And some photos of the manufactured parts plus an original....
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Thread: Manual lathe for large diameter turning |
21/10/2017 20:38:54 |
A Binns and Berry machine would certainly do the job, not sure we have the floor space for a machine that long though. |
21/10/2017 11:52:29 |
Vertical borer looks interesting especially if we could fit a drilling spindle to the tool post as there are some holes to drill on a PCD Edited By JasonB on 21/10/2017 13:11:22 |
21/10/2017 11:12:54 |
Hi Andrew, Thanks, ill have a look in to a vertical borer, I think that is how they are being machined at the moment. I have asked admin to delete this thread as the title is wrong. not sure how my name got in there. Mike Edited By JasonB on 21/10/2017 13:10:40 |
21/10/2017 11:10:19 |
I'm investigating bringing some machining back in house (actually back to the UK) but we would need a gap bed lathe capable of turning a diameter of ~900mm. So far I have been searching for both new and used machines, as a DRO will be used I'm not worried about it being metric or imperial. Material being machined is aluminium and as the part is a ring only about 150mm travel is required. Depth of part is about 100mm. Not much luck so far and some distributors swapping between radius and diameter for the swing over gap isn't helping much. Any help or suggestions of brand to look for would be much appreciated. |
Thread: Manchester Model Eng. Exhibition. |
19/02/2017 15:47:53 |
Spent the morning at the show yesterday, looked well supported by local clubs and visitors. The show felt twice as big as last year with a good mix of exhibitors and trade, hopefully it will continue to double in size each year and become a main event on the calendar. |
Thread: Possible new ideas for Model Engineers' Workshop |
07/09/2016 08:02:56 |
I would second Stephen`s suggestion for a silver soldering and brazing article but written as a tutorial including example practice joints/applications of increasing complexity as the articles progress. Each tutorial could include what to look for when it goes wrong and how to improve. |
Thread: Is CNC cheating |
03/09/2016 22:57:54 |
In my opinion it's the fabrication aspects of models that separate the good models from the exceptional models and CNC won't help much with this. The machining side is easy in comparison. Thanks for the clarification Jason. |
03/09/2016 17:06:56 |
Hi Jason, Will this mean that someone who submits an entry built to someone else`s design gets 0 marks for this section? and the person that designs everything from scratch gets the full 20? This 20% would give a significant advantage in a competition and give someone without Rolls Royce quality machining skills a fighting chance at a trophy....
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02/09/2016 21:12:17 |
From experience it is just as easy to produce a part with poor surface finish and poor accuracy on a CNC machine as it is on a manual machine, quite often with costly consequences to the machine and tooling! I haven't seen many (if any) libraries of parts that one can simply download and machine to produce a model of any kind. Therefore to produce a part on a CNC machine the engineer will have to program the part in G code or model the components in CAD and let the software generate the G code then produce all the fixtures as normal. To do this they will need all the knowledge of the materials and tooling to ensure depth of cut, feeds and speeds are correct as the machine wont back off if it 'feels' its not quite right. In my opinion it takes more engineering knowledge and skill to produce a good part on a CNC compared to a manual machine. Those that consider it cheating don't have the appreciation for the amount of prep work required before the machine starts to cut. The most used machine tool in my workshop is my manual lathe, the CNC lathe hardly gets used! Sadly I do not believe that the enormous effort required to get the CNC machine going will be taken in to account in judging at competitions just the same as the effort that goes in to 'own design' projects and engineering drawings e.t.c....needs further consideration to ensure new creations are brought on to the exhibition scene but this is another subject for debate... |
01/09/2016 10:35:47 |
I don't believe anyone genuinely believes you can just download a model, press a button and the part falls out?? Don't forget there is a significant difference between industrial CNC machines that some will have seen as part of their job and on youtube and the machines that the average model engineer has access to. I doubt many model engineers have a 5 axis machine with a carousel loaded with exotic tools driven by the latest CAM software with all the bells and whistles and full support from the supplier. I have a mixture of both in my workshop and upon entering CNC I had to do a lot more 'technical' research and calculations for feeds, speeds and types of cutters compared to machining by feel/trial and error. The engineering skills I have allowed me to convert this theory in to practise as an alternative to years of practical machining experience (I had some). I would argue that this is an additional skill and by no means a less demanding task. I have been stuck with the same jigs and fixtures on the CNC that I use on manual machines. Working as a design engineer I get parts made all the time and tooling charges are still the biggest expense. There are some clever clamping systems about but most machine shops don't have them or don't use them if the jobs are 1 offs or small batch. I rarely make use of the 3D machining capability I have with CNC as it takes too long to machine and is not required for the majority of my work. Don't forget to make the most of this you also need the skill of using 3D CAD, a skill that many have tried and failed to master. Judges need to ensure they have a general knowledge of all manufacturing methods available to the model engineer to ensure that they truly appreciate the effort that has gone in to making a part. Also, with respect to all machine operators out there, there is a big difference between machine operators and CNC programmers. As model engineers using CNC we have to be both. |
Thread: Identifying donor crankshaft |
06/08/2016 15:12:54 |
I have had a look at scooter crankshafts and although it looked quite positive at first I think the one I have has come from a chainsaw, albeit an old one. My only requirement now it to find one with a similar diameter shaft and length (before the taper), if that search fails then I`m going to investigate making one, materials and heat treatment e.t.c I called in to my local lawnmower/chainsaw repair shop and he looked at me in horror and basically refused to help me without a specific code to order an equivalent replacement. He was not prepared to help and show me anything similar incase anything came back on him in the event of the part failing. How ridiculous, no wonder this country is being left behind when it comes to innovation. |
04/08/2016 21:17:51 |
Hi John, Thankyou for the info, I will check out Solex engines and see if I can see a match. The flats on the end of the crank pin were ground on to accept a 'new' section for the crankshaft, the old one being 3 pieces pressed together. I`m thinking the half of the crankshaft I have must be screwed or pressed together as I cant see how they can press the bearing over a ~1mm step. The plan at the moment is to find something similar rather than an exact replacement which is still proving difficult and the technical departments of the major manufacturers don't seem interested in helping. A repair shop may be more helpful which is this weekends challenge. |
02/08/2016 22:36:44 |
Evening! I`m trying to identify a crankshaft that was used in a friends model aero engine project as I would like to build a similar engine. Sadly he has passed away so I cant ask him where he got it from but I have been told it came from a chainsaw. I`m not having much luck identifying a crankshaft long enough to take 2 bearings. I have attached some photos and a drawing, if anyone has any experience in engines from chainsaws, cut off saws or similar sized engines any help or direction would be much appreciated. |
Thread: Meet Up at Doncaster! |
21/05/2016 11:20:29 |
We went to Doncaster Yesterday. A nice venue, high-tech and good facilities. As the weather was warm it was nice to be able to sit outside and have a drink, it was starting to warm up inside the exhibition!. After a 3 hour journey it was a shame to be greeted with complete mayhem in the car park with people getting turned around and redirected out by a NHS park and ride attendant, we found the parking that was about a 10min walk away from the venue. The show felt smaller than Harrogate with less models on show, or was this because they were split up? The models that are on display are of a very high standard and well worth seeing. It would be nice to see more activity outdoors but I guess this is down to those willing to display their models. We found the displays upstairs by accident when we went up for a drink. A few of the smaller regular traders were missing, Home and Workshop have a nice big stand where I always find some nice tooling to add to the collection. A very interesting 3D printing stand with machines and printed parts on display. I`m not familiar with what other facilities Doncaster racecourse has but there didn't seem to me much room in the hall for expansion or to accommodate the missing exhibitors/traders. Still an enjoyable day out but I would be happy for it to return to Harrogate or a larger venue.
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Thread: Tilting Table Kit? |
26/04/2016 10:04:48 |
I have the 559 castings from CES so not as robust as the one shown in your second link. I wasn't too bothered about a scale as I plan on measuring the angle each time it is set and clamped.
Edited By Michael Checkley on 26/04/2016 10:05:57 |
Thread: Buying a 3D printer, but which one? |
23/04/2016 12:51:07 |
Thankyou Andrew for adding the photos. It was seeing your real life applications that helped me make my mind up. Surface finish is an interesting debate as given the way the technology works it will never be 'perfectly' smooth. From the samples I have printed I have been impressed with the surface finish given by the Ultimaker (the Zortrax was even better on ABS) and I would say the surface finish is far better than the shockingly bad castings us model engineers are happy to purchase. No need to predict the future of 3D printing just go in to any major industrial player and see for yourself. I took some samples in to work to show my colleagues and have already been asked to write a proposal for getting a more industrial machine installed. |
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